Questions regarding external hard drives

Interfaces

E-SATA
+Fastest(Just like in the computer)
+Hot pluggable on many boards
-Not all computers have it(since you on backup it does not matter)
-Some boards will not like hot plugging

FireWire
+Faster then USB but still slower then E-SATA.
-Not all machines have firewire.

USB
+Works on almost any computer
+about 35 megs/sec is ok for most people
-SLOWWWW

Failure.

Since your drive will have minimal uptime since its running only for backups heat and failure are not going to be much of an issue.
Most drives seem to fail about the same from what i see.
Google did a test with drive failure rates and said that heat was not as much of a factor as some think.
I have a external 500 with NO vents used for back-ups and i took it out once and checked the smart stats and it was never overly hot. so i think that user just got a bad drive.

Other thoughts

I find the software Second Copy works very well as it automatically checks for and only sends files that have changed(this keeps backup times fast since you are not sending everything over and over again). It can be set to delete file deleted on the source drive and even keep backups of changed files. Running automatically for lets say a networked drive or manually for an external drive. In other words i DO recommend this software for its easy to use interface.

Links:
http://www.secondcopy.com/ - Second Copy software(There is a demo)
http://research.google.com/archive/disk_failures.pdf - Google Disk failure study(Long)

Hope this helps.

For that kind of usage, speed won't really be an issue.....this may be very attractive for you.

As far as "ratings" go, I'd take a look at the reliability ratings over at storagereview.com. WD has consistently been lowest of late with their last 3 models coming in in the 4 %, 5% and 12% percentiles.....that means, say for the 4% percentile they were more reliable than 4 %, and less reliable than 96% of all the drives in the survey.

USB has more overhead then firewire. due to this even firewire 400 is faster.

480(quite a nice marketing term just like how 54megabit wireless never goes over 50 % due to the collision avoidance system of resending every packet back to confirm it made it ) megabits is 60 megs per second but you will NEVER find a usb drive enclosure that runs that fast I have a lot of usb enclosures and they all cap in the 30 - 35 megs/ sec area....

If you look here you will see that usb tends to just get past 30 and firewire 400 just gets past 40. so firewire is still faster.
http://www.tomshardware.com/2006/1 [...] erformance